Language changes all the time. Some changes really are chaotic, and disruptive. Take decimate, a prescriptivist shibboleth. It comes from the old Roman practice of punishing a mutinous legion by killing every 10th soldier (hence that deci- root). Now we don’t often need a word for destroying exactly a 10th of something – this is the ‘etymological fallacy’, the idea that a word must mean exactly what its component roots indicate. But it is useful to have a word that means to destroy a sizeable proportion of something. Yet many people have extended the meaning of decimate until now it means something approaching ‘to wipe out utterly’.
Descriptivists – that is, virtually all academic linguists – will point out that semantic creep is how languages work. It’s just something words do: look up virtually any nontechnical word in the great historical Oxford English Dictionary (OED), which lists a word’s senses in historical order. You’ll see things such as the extension of decimate happening again and again and again. Words won’t sit still. The prescriptivist position, offered one linguist, is like taking a snapshot of the surface of the ocean and insisting that’s how ocean surfaces must look.
Be that as it may, retort prescriptivists, but that doesn’t make it any less annoying. Decimate doesn’t have a good synonym in its traditional meaning (to destroy a portion of), and it has lots of company in its new meaning: destroy, annihilate, devastate and so on. If decimate eventually settles on this latter meaning, we lose a unique word and gain nothing. People who use it the old way and people who use it the new way can also confuse each other.
I'm taking this a little out of context. The author of that article is actually tolerant of linguistic drift.
But the last paragraph really sums up how I feel. Using a very specific word like decimate to mean something else like annihilate (for which a perfectly good word already exists) is a proposition with no up-side. A perfectly good specific word is lost and dumped into a cauldron where a miasma of similar words are already swirling, all losing their specific meanings and becoming a stew of interchangeable vaguely-similar terms.
